OSHA previously had no occupational exposure limit for phenothiazine. The Agency proposed an 8-hour TWA PEL of 5 mg/m3for this substance, with a skin notation; the final rule establishes this limit and a skin notation, which are consistent with the recommendations of the ACGIH. NIOSH (Ex. 8-47, Table N1) concurred with OSHA's proposed limit for phenothiazine.
OSHA is basing the PEL for phenothiazine primarily on the findings of a study by Mawhinney and Rakow (1968, as cited in ACGIH 1986/Ex. 1-3, p. 472) that showed that exposure to 15 to 48 mg/m3 of phenothiazine was associated with skin sensitization but not with other acute systemic effects. Symptoms of sensitization in workers included burning and itching of the skin. Accompanying these sensitization reactions were pinkish-red-colored hair and brown fingernails. Phenothiazine has been reported to cause photosensitization of the skin, and intense irritation and itching of the skin have been associated with inhalation of phenothiazine spray (ACGIH 1986/Ex. 1-3, p. 472).
In the final rule, OSHA is establishing an 8-hour TWA PEL of 5 mg/m3, with a skin notation; this limit is below the exposure range that has been shown to cause sensitization reactions in workers. OSHA concludes that the uncontrolled occupational exposures to phenothiazine that were possible in the absence of an OSHA limit pose a significant risk of sensitization, which is a material impairment of health. Accordingly, the Agency is establishing an exposure limit that will substantially reduce this significant risk.